1. Field of the Invention
This invention relates to the keypad entry of data. More particularly, this invention relates to the entry of alphanumeric data using a keypad having more than one alphanumeric character assigned to a key.
2. Description of the Background Art
Historically, a conventional “rotary” telephone included a rotary dial with 10 finger-holes, numbered 1-9 and 0, that allowed a person to sequentially dial each numeric digit of the desired telephone number to be called. With the age of the transistor, electronic telephones with dual tone, multiple frequency (DTMF) keypads that included 10 numeric keys labeled 1-9 and 0 came into widespread use and completely supplanted the conventional rotary telephone.
The conventional DTMF keypad commonly included two additional unnumbered keys labeled * and #. Combined with the numbered keys, the topography of a conventional DTMF keypad therefore comprised a 3×4 layout with the 0 key positioned in the 4th row between the * and # keys, for a total of 12 keys. With considerable foresight, the manufacturers of DTMF keypads also assigned and labeled the 26 letters of English alphabet to the numbered keys (excepting key 1) to allow the DTMF keypad to enter of alphanumeric data. Commonly, if not universally, key 2 was labeled with the letters A, B & C, key 3 with D, E & F, key 4 with G, H & I, key 5 with J, K & L, key 6 with M, N & O, key 7 with P, Q, R & S, key 8 with T, U & V, key 9 with W, X, Y & Z.
Various “multitap” techniques were devised, with appropriate decoding circuitry, to allow the selection of the desired alpha character by multi-tapping the key containing the key to which the alpha character is assigned. The most prevalent multitap technique included pressing the key labeled with the desired alpha character the number of times equal to the position of the alpha character on the key, and then either waiting for a default time-out period or pressing a different key. For example, when the letter B is desired, key 2 is pressed twice, represented by the fact that the letter B is located in the second position on key 2. Correspondingly, when the letter C is desired, key 2 is pressed three times, represented by the fact that the letter C is located in the third position on key 2. Representative early patents that teach multi-tapping techniques and appropriate decoding circuitry include U.S. Pat. No. 4,307,266, U.S. Pat. No. 4,532,378 and U.S. Pat. No. 4,608,457, the disclosures of which are hereby incorporated by reference herein.
Early implementations of alphanumeric DTMF keypads allowed the deaf to communicate using a conventional telephone. In the 1980's, telephones with alphanumeric DTMF keypads became essential to interactive voice response telephony systems that required alphanumeric data to be entered. In the 1990's, alphanumeric DTMF keypads came in widespread use to enter alphanumeric data for telephony small messaging services (SMS). More recently, conventional alphanumeric DTMF keypads, and other reduced-key alphanumeric keypads with multiple alphanumeric characters assigned to one or more keys, have been ubiquitously employed in a host of other applications to enter alphanumeric data, such as but not limited to personal digital assistants and instrumentation.
Unfortunately, as discussed above, conventional multitap techniques necessitate the pressing of a key a multiple of times to “scroll” through the multiple characters associated therewith to select a single alphanumeric character. For example, in a conventional DTMF keypad referenced above, the respective keys 2-9 must be depressed twice to select the letters B, E, H, K, N, Q, U and X and three times to select the letters C, F, I, L, O, R, V and Y, whereas respective keys 7 & 9 must be depressed four times to select the letters S and Z. Indeed, whenever multiple alphanumeric characters are assigned to a particular key in reduced-key alphanumeric keypads, excessive depressing of the respective keys is required to scroll through the associated alphanumeric characters.
Presently there exist various techniques for minimizing the number of depressions of the multi-character keys of a reduced-key alphanumeric keypad to scroll through and select a particular alphanumeric character associated therewith. One common approach is to employ a dictionary database and to then predict the desired alphanumeric character based upon the entry of alphanumeric characters that match the most commonly used words in the dictionary.
For example, Tegic Communications (http://www.t9.com) provides a dictionary-based software application, identified by the trademark “T9”, that reads a string of keystrokes and then sequentially presents the most commonly used words from a language-specific dictionary corresponding to the alphanumeric characters associated with such keys. To illustrate, the English dictionary database could include the word “how” and could prioritize it as the most-commonly used word associated with the DTMF keystroke sequence 4-6-9. Then, upon the entry of the keystroke sequence 4-6-9, the word “how” is displayed and offered for selection by the user. If “how” was the intended word, it would have been selected with only three keystrokes (in contrast to the multitap technique discussed above that would have required six keystrokes). If “how” was not the intended word, the user may then depress a key designated as the “next” key to instruct the program to display the next most commonly used word. If repeated depressing of the “next” key does not display the desired word, the desired word may be manually entered into the dictionary using the multitap method.
T9 has achieved substantial commercial success but requires considerable memory for storing the language-specific dictionary. Moreover, since the dictionary is language-specific, T9 is not particularly suited for multi-language use or other less common implementations that often employ acronyms, abbreviations, scientific words or the like.
Representative patents assigned to Tegic Communications, Inc. relating to its T9 software, the disclosures of which are hereby incorporated by reference herein, include:
PAT. NO.Title6,307,549Reduced keyboard disambiguating system6,307,548Reduced keyboard disambiguating system6,286,064Reduced keyboard and method for simultaneous ambiguousand unambiguous text input6,011,554Reduced keyboard disambiguating system5,953,541Disambiguating system for disambiguating ambiguous inputsequences by displaying objects associated with thegenerated input sequences in the order of decreasingfrequency of use5,945,928Reduced keyboard disambiguating system for the Koreanlanguage5,818,437Reduced keyboard disambiguating computer
Another common approach for minimizing the number of depressions of the keys of a reduced-key alphanumeric keypad to scroll through to select a particular alphanumeric character associated therewith, is to employ a linguistic-based algorithm that predicts the desired alphanumeric character based pre-defined linguistic rules. For example, Eatoni Ergonomics, Inc. provides a software program sold under the trademark “Letterwise” that includes a number of linguistic rules that predict the desired letter of a depressed multi-character key based upon the previous entry of other characters. A simple example of a linguistic rule is to offer the letter “u” upon depressing the multi-character (T, U & V) key 8 whenever the previously-entered letter is the letter “q”, since neither the letters “t” or “v” would linguistically be appropriate. The linguistic theory employed is disclosed in Eatoni's patents including U.S. Pat. No. 6,885,317, entitled “Touch-typable devices based on ambiguous codes and methods to design such devices” and U.S. Pat. No. 6,219,731 entitled “Method and Apparatus for Improved Multi-Tap Text Input”, the disclosures of which are hereby incorporated by reference herein.
Like dictionary-based T9, linguistic-based Letterwise is language-specific. Letterwise may be preferred in scientific applications that employ less-common words since even scientific words are often linguistic-based and fewer keystrokes would probably be necessary. However, both T9 or Letterwise are unable to predict uncommon acronyms or abbreviations, such as in a military application.
Still other representative patents that disclose algorithms for predicting a desired character (or words) based upon the entry of previous characters (or words) may be found in the following US patents, the disclosures of which are hereby incorporated by reference herein.
U.S. Pat. No.Title5,952,942Method and Device for Input of Text Messages from aKeypad5,974,121Alphanumeric Message Composing Method usingTelephone Keypad6,052,443Alphanumeric Message Composing Method usingTelephone Keypad6,054,941Apparatus and Method for Inputting IdeographicCharacters6,137,867Alphanumeric Message Composing Method usingTelephone Keypad5,828,991Sentence Reconstruction using Word AmbiguityResolution5,960,385Sentence Reconstruction using Word AmbiguityResolution5,031,206Method and Apparatus for Identifying Words Entered onDTMF Pushbuttons5,903,630Method and Apparatus for Specifying AlphanumericInformation with a Telephone Keypad6,150,962Predictive Data Entry Method for a Keyboard6,346,894Method and System for Intelligent Text Entry on aNumeric Keypad6,643,371Method and Apparatus for Alphanumeric Data Entry5,911,485Predictive Data Entry Method for a Keypad6,799,303Speed Typing Apparatus and Method
Therefore, it is an object of this invention to provide an improvement which overcomes the aforementioned inadequacies of the prior art methods and provides an improvement which is a significant contribution to the advancement of the art.
Another object of this invention is to provide an apparatus and method for the entry of alphanumeric data using a keypad having one or more alphanumeric characters assigned to each key, wherein a rule tree defining the prediction associated with a depressed key is built based upon the previous selection of characters and is also weighted based upon the number of times the rule tree previously correctly defined the prediction to thereby increase the probability of predicting the desired character and to be quickly adaptable to different users having different language styles or vocabularies
The foregoing has outlined some of the pertinent objects of the invention. These objects should be construed to be merely illustrative of some of the more prominent features and applications of the intended invention. Many other beneficial results can be attained by applying the disclosed invention in a different manner or modifying the invention within the scope of the disclosure. Accordingly, other objects and a fuller understanding of the invention may be had by referring to the summary of the invention and the detailed description of the preferred embodiment in addition to the scope of the invention defined by the claims taken in conjunction with the accompanying drawings.